1. Technical Field
The present invention relates to food products and to their methods of preparation. More particularly, the present invention relates to dairy products, especially cultured dairy products such as yogurt, which contain added materials of differing texture such as crisp cereal pieces and to their methods of preparation.
2. Background Art
Yogurt is a nutritious dairy product which recently has become quite popular. At retail, yogurt is now available in a wide assortment of varieties of texture, fat content and flavor among other attributes. Other than aseptically packaged yogurt, yogurt is traditionally distributed and consumed with a live culture which requires refrigerated distribution. Broadly, yogurt products fall into either the custard style (i.e., a set firm gel) or the stirred style, i.e., wherein the gel or curd is broken up by stirring. One popular style is fruit-on-the-bottom, also colloquially referred to as "sundae" style in which a layer of fruit preserves is on the bottom of the yogurt container and the custard yogurt fills the rest of the container. Still another style is western style which comprises a bottom layer of fruit preserves plus a top layer of stirred style yogurt. Another style of yogurt comprises a stirred admixture of fruit preserves and yogurt often referred to colloquially as "Swiss" style. More recently, a variation of Swiss style additionally comprises an admixture of nuts and/or partially puffed cereal grains with the yogurt. This yogurt mixture is sometimes referred to as "breakfast" style yogurt. The partially puffed grains and nut pieces give a pleasingly mixed organoleptic texture which is both chewy and crunchy in addition to the creamy mouthfeel of stirred yogurt.
While quite popular, the inclusion of partially puffed cereal grains are not without problems or limitations. Partially puffed cereals grains (i.e., having a bulk density of roughly 0.3 to 0.5 g/cc.) are employed rather than fully puffed cereal grains (i.e., having a bulk density ranging roughly from 0.1 to O.2 g/cc.). Fully puffed cereal grains or pieces (2.5% moisture) being considerably drier than the high moisture yogurt (90% moisture) absorb moisture over time resulting in a loss of crispness and the development of a soggy texture. Partially puffed cereal grains, however, tend to remain chewy notwithstanding moisture absorption. It would be desirable to provide yogurt products comprising the more crunchy, crisp, fully puffed cereal grains or other relatively dry, puffed pieces such as puffed cereal dough pieces rather than being merely chewy.
The food art includes many attempts at the inclusion of one relatively drier material dispersed throughout a second material which is relatively more moist. Generally, the success of such approaches depends, inter alia, primarily in the water activity differential between the two differing materials with severity directly proportional to this differential. Providing a product (A.sub.w of 0.7 to 0.9) comprising yogurt and puffed cereals, (A.sub.w of 0.1 to 0.3) or similarly dry materials, e.g., ready-to-eat cereal pieces, especially puffed cereals, presents an enormous challenge since the two materials differ so greatly in water activity.
One successful approach involves the complete segregation of the two different materials into separate containers. Although successful, this solution lacks convenience, is expensive and can result in increased packaging waste. The art also includes numerous attempts at the provision of dual compartmented containers with an intermediate barrier, usually inedible, but sometimes with an edible barrier, (see, for example U.S. Pat. No. 4,820,533 issued Apr. 11, 1989 to Seaborne et al.). Again, while successful, such products are not as convenient or as inexpensive as a single container.
Still another approach has been to include an edible coating to the drier food pieces. Edible, solid fat-based coatings have been tried many times. Barrier effectiveness increases with fat hardness and coating thickness. However, solid waxy clumps of fat are not organoleptically or nutritionally appealing additions to yogurt whether or not they contain crisp cereal pieces. Furthermore, such barriers exhibit only limited protection over time. The fat-based barriers tend to develop cracks or pinholes over time. Thinner barriers sometimes employing shellac-based coating compositions have also been tried, (see, for example, U.S. Pat. No. 4,710,228 issued Dec. 1, 1987 to Seaborne et al. entitled Edible Coating Composition and Method of Preparation). However, these materials work best on smooth surfaced pieces. Irregular surfaced pieces such as puffed cereal grains are difficult to coat effectively.
Given the present state of the art in the provision of high moisture foods, there is a continuing need for new and useful ways to provide an admixture of high moisture and low moisture foods which provide the desirable organoleptic texture contrasts and which are convenient to use and consume yet maintain their disparate texture over conventional distribution and storage times and conditions.
Surprisingly, the above difficulties and limitations have now been overcome and the present invention satisfies a long felt need to develop yogurt products, especially sundae and/or western styles, having crisp, relatively dry cereal pieces but without a discrete intermediate barrier. The present invention resides partially in the dispersion of the dry pieces in an emulsion matrix comprising a specially defined water-in-oil ("w/o") emulsion. The emulsion essentially comprises a high solids water phase in a continuous, liquid oil phase which oil phase is gelled.